Protractor.



F. PROBST.

PROTRAGTOR.

APPLIUATION FILED 0012.15, 1908.

935 ,869., 1 Patented Oct. 5, 1909.

W i e lai/Z17- INVENTOR UNITED STATES "Pnfigiinfr ormoni FRANK raons'r,or ELIZABETH, New JERSEY.

4Specification of Letters'Patent. i

llatenten oct. 5, 1909.

application mea october 15, ieos. serial No. 457,775.'

To' all whom ttf/nay concern- Be it known that I, FRANK PnoBsT, acitizen of the United States, residing vat Elizause the same, referencebeing had to the` accompanying drawings, and to gures of referencelnarked thereon, which form a part of this speci'cation.

This invention relates to a has a casing in which abla e is pivotallymounted, the blade being adapted to swing,

Yand having,lon its hub, a scale to indicate 'the degree assumed bytheblade in its relation with the casing, these marks being preferably onefor every ten degrees and adapted to register with a zero mark on thecasing, the blade being adapted to swing with one end within the casing,the casing having a stop to limit the entrance of the blade in thecasing, whereby they are held in parallel relation.

The device further consists of a means in the casing for Ylocking theblade in any position.

.A still further lobject of the invention is to provide an arm having apointer projecting up through a slot in the casing, the slot having, onits edges, marks to indicate single degrees or fractions thereof andremoved at a considerable distance from' the hub of the blade so thatthe multiplication'of the movement, by reason of the long arm, makes thereading of'the single degrees and parts thereof an easy matter,andprevents the necessity of supplying thehub with such minutegraduations as are now necessary. This arm, with its pointer, is limitedby the length of the slot so that when ten degreeshave been traversed bythe pointer it stops-and there is a sliding or step-by-st'ep connectionbe-4 tween the arm and the hub of the blade so that the blade can berotated, but-wherever it is stopped the pfointer will be in swingingrelation therewith. The blade is adapted to slide on its pivot from itscenter toward one end'so that it can be used in any numbei' ofsituations.

The invention is illustrated in the accompanying draw1ng,'1nl.wlnchlFigure 1 is a face View of the device. Fig.

rotractor thaty ing into the upper member of the casing. Fig. 4 is aface view of the interior of the lower member'of the casing. Fig. 5 is asection of all the parts, and Fig. 6 is a detail showing the connectionbetween the blade slidably connected therewith.

i The inventionconsists of a casing consistying-.of two members 10 and11 which are Vollowed out onftheir opposite faces to forni members'ofthewcasing, on one end, and is rovl'ded with a slot 13 which its over aYlate 14 shown in Fig..6, this plate having. a

shown moreparticu'larly in Fig. 5, this screw also acting to hold theparts together on that end of the'protractor. The plate 14 Yis providedwith pins 17 vwhichpro3ect up through a hub 18 which turns with theplate 14 and scale 19 having Aits marks adapted 'to register with a mark20 on the casing to indicate the .degrees established` between the bladeand the casing in their various positions. 'lhcse degrees are wideenough apart to be plainly read, and are not made necessarily minutesingle or digit degrees are not indicated on the hub. The pinsl alsopass through Openings 21 shown-more particularly in Fig. 3, theseopenings being made in `a toothed wheel 22 having teeth, the recessesbetween the teeth being in register with the marks ot' the scale on thehub 18that is, there is a tooth between each two marks so that thetoothed wheel 22 is in the saine constant relation with the hub-18.

as a casing therefor, and being ground to fit into vthe member' 10, is aholder having au arm 24 in extension thereof, the arm 24 ending up in apointer 25 which projects up'into a slot 26. in the easing, preferablyin the member 10, this slotlbeing a considerable distance from thecenter of the pivot of the blade so -that the'distance increases themovenumber of degrees betieen each of the marks 19 on the hub'18 areeasily read. stem 27 is mounted in a block 28 in the arm 24, and passesinto the hub 23 and has a rounded end 29 which isl adapted to fit in andits hub, whereby it is rotatably and also chambers. A blade 12 swingsbetween thev ange 15 surrounding the pivotal screw 16,

consequently with the blade 12, and has thereon 4'the'scale 19 shown inFig. l, this ment, and the scale marks 26a indicating theI 2 is a sideView, and Fig. 3 is a view look- .for reasons hereinafter described,since the Surrounding the toothed wheel and ating A V between the teethofl the wheel 22, but also is adapted to be slid back to allow `theteeth to pass over it when the pointer gets to the end ofthe elo andthereby acts to stop the erin spring 3G keeps the siem normally with itsend in Contact with the toothed edge of the Wlieei 22, and it will be.readily seen from this construction that the pointer swings freely with'the blade between the ends of the slot, but when it gets to che end ofthe slot the blade will continue to swing, carrying the toothed Wheel 22with it,

the teeth will `fiole over the end 29 oi`- the stem 27 until. thedesired point is reached, when the arm 2li and its pointer 25 will againswine' freely with the blade. The lade has aieveled end 3l which, whenit is closed, lits against the surface 32 in Fig. li, which nots 'tolimit the movement of the blade. j

ln the member 1l and surrounding the pivotal screw 1i) are the twopieces 39- which ere in the shape of cones, the upper one having aiizinge 33,' and a yoke 54l with a iL shaped interior Surface 35 shown,in Eig. 5 {its around the two conical pieces A sliding wedgc-shepecflpiece 36 is pressed toward the pivotal pin by reason oit' the screw 37with. its 'thumb-piece 38, and the beveled faces 3f) are forced togetherso that the two oonicalpieces 82 are forced apart and bind against theplate lli, as shown in Fic; 5, whereby all the parts are locked in'position.

This protractor is simple, and is not e' construction to get out oforder, and has a 'seele thatfis very simple to read, since it has no 1minute sub-divisions on its scale.

CII

Having thus described my invention, what I clairn isil. A pi'otmctorcomprising a easing formed of two members having e slot betweenthem, ablade pivoted in one end of the siotl and adapted to swing therein, theopposed faces of the members being recessed, one of 'the' membershaving: sot concentric to "the pivot of the blade and adapted oonneetwith the recess, a hub turning in the easing.

and secured to the blade and having *radium tions thereon to registerimn the casi en arm having a pointer th" "n to p through the slot, thepoint r being. ,need to register with the graduations on the cesingadjacent to the curved slot, ineens 'for causing the erin to swing withthe n b, but to bein sliding engsweme'nt, 'with when. the poin'l'cr engtue ends ci ne end.

@einem curved slot, the arm in its operative eonnec tion with `the hubbeing placed in the recess of one member o1 the casing, and means forlocking theh'ub of the blade, the locking ineens being placed inthe'recese ol' the other,

the teeth on the Wheel, a pair of rings with beveled faces, a split yokewith a 'lf-shaped yinterior to engage the beveled .faces oi" the rings,e. slidingvedge to engage the yoke to compress it, and a inanuelljvoperated means for sliding the Wedge.

A protrnctor comprising a casing, a blade swinging in the casing, a pinin the casing on which the blade is pivoted, rings on the nin havingouter beveled feces, a split yoke with a lifSl'ieped interior to engagethe beveled feces of 'the rings, o Wedge adapted to slide and havingbeveled feces to press the yoke together, and means projecting from thecasing for manually operating the Wedge.

et. A protractor comprising a casing, a

blade swinging inthe casing, a pin in theA ivotedmin s casing `on whichthe blade is on the pin having outer bevele feces, a sp it voire with aii-shaped interior to engafre the beveled :5e-.ces .of the rings, nWedge a opted to., slide end having beveled faceseo press the yoketogether, means projecting ioni 'the casing for manually opereting theWedge, a.

screw bearing onl'the wedge to force it in one direction, Boring notionof 'the yoke tending to i'etnm it, and a means for manualiy. operatingthe screw on its projecting in testimony, that l claire the foregoing,have eieunto set my hand this 7th dey of (ic'lobei', 19158..

Fitilli PSBST.

1ikv/itnesses Senese, Rini., (l. .Pnnacnen

